Electric switch



Feb. 4, 1958 H. KARLSS'ON 2,822,440

ELECTRIC SWITCH Filed June '26, 1956 /2\ K o 2 T I 1NVENTOR fizya 76.5 550 ELECTRIC SWITCH Helge Karlsson, Huddinge, Sweden, assignor to Svenska Reliifabriken A B, Stockholm, Sweden, :1 Swedish jointstock company Application June 26, 1956, Serial No. 593,983

Claims priority, application Sweden June 28, 1955 4 Claims. (Cl. 200-74) The present invention relates to an electric switch of the pressure operated type and has for its object to provide a switch which is simpler and more reliable in operation than previously known switches of this type.

The switch according to the invention comprises a movable contact member carried by a resilient arm which also carries a butt member arranged to cooperate with a locking member. The butt member and the locking member are so arranged that When the resilient arm is in nonoperated position, the butt member is situated in the path of travel of an operating member, and so that when the resilient arm is moved to operated position by the operating member acting upon the butt member, the locking member actuated by a directional force, e. g. a spring force, is moved into engagement with the butt member and thereby retains the resilient arm in operated position at the same time as the locking member is moved into the path of travel of the operating member, so that the latter when operated again after having been restored to its home position acts upon the locking member and moves the latter from engagement with the butt member whereby the resilient arm is released and returns to its non-operated position due to its elasticity.

The invention will be described more in particular in conjunction with the accompanying drawing in which Figures 1 to 4 show schematically a simple embodiment of the invention. The different figures show the switch in different positions.

In the figures numeral 1 designates the frame of the switch. The frame is made of insulating material. A supporting member 2 is attached to the bottom of the frame 1 and carries a stationary contact member 3. A movable contact member 4 mating with the stationary contact member 3 is attached to one end of a resilient arm 5 the other end of which is anchored in the frame 1. The resilient arm 5 also carries a butt member 6.

An operating member 7 in the form of a somewhat resilient leaf spring runs through an aperture in the frame 1. A push button 8 by means of which the leaf spring can be displaced in longitudinal direction is attached to that end of the leaf spring 7 which is situated outside the frame or envelope of the switch. Between the push button 8 and the frame 1 a coil spring 9 is provided which surrounds the leaf spring 7 and serves to restore the operating member to the home position when the push button 8 is no longer operated. A stop member 16 is attached to the leaf spring 7, and when the leaf spring 7 is in its initial position, this stop member abuts against the frame 1 thereby preventing the leaf spring from further upward displacement.

A post 16 is also attached to the bottom of frame 1, and a lever 11 is pivoted on the upper end of this post. A spring 12 is so arranged that it strives to turn the lever 11 clockwise about the pivot. At its free end the lever 11 is provided with a butt surface 13 and a hook-shaped extension 14.

Figure 1 shows the switch with the resilient arm 5 in its States Patent '0 ice non-operated position. The upper concave V-shaped surface of the butt member 6 is then situated below the free end of the operating member 7, and the hook-shaped extension 14 of the lever 11 abuts by its outer side against the butt member 6 due to the action of spring 12.

Figure 2 shows the switch with the push button -8 pushed down. The operating member 7 'has now by its free end pushed the butt member 6 and also the resilient arm 5 downwards so that the movable contact member has been brought into contact with the stationary contact member 3. Since the butt member 6 does not now abut against the outer side of the hook-shaped extension 14, the lever 11 is rotated due to the action of spring 12 so that the hook-shaped extension 14 extends over the upper surface of the butt member 6. However the lever 11 will be arrested by its surface 15 striking against the butt member 6.

When the push button 8 is released, the operating member 7 is restored to its initial position by the spring 9. The butt member 6 will then move upwards due to the elasticity of the arm 5. The switch then assumes the position shown in Figure 3. The hook-shaped extension 14 of lever 11 now catches the upper surface of the butt member 6 and thus retains the resilient arm 5 in its operated position. Furthermore the surface 13 on the lever 11 is now positioned below the free end of the operating member 7 and is thus located in the path of travel of the operating member 7 when the button 8 is again pushed down.

The latter case is illustrated in Figure '4. Here the push button 8 has been pushed down again whereby the free end of the operating member 7 has been pressed against the butt surface 13 on lever 11. The surface 13 is concave, and since the leaf spring 7 is flexible, its lower end will first glide along the surface 13 until it has reached the lowest part of the surface 13. This part of the surface 13 is so located in relation to the pivot of lever 11 and to the main extension of the leaf spring 7 that when the leaf spring 7 is further pressed against the surface 13, a turning moment will be exerted on the lever 11 which will then be turned (counter-clockwise in the embodiment shown) so that the hook-shaped member 14 is disengaged from the butt member 6. The arm 5 is then restored to its initial position by its own elasticity. Since the lower end of the leaf spring 7 is now flexed aside, the butt memher 6 will not strike against the leaf spring 7 during the return movement of the arm 5. When the push button 8 is thereafter released, the switch is restored to the condition shown in Figure 1. v

The locking member, i. e. the lever 11, is preferably arranged at the side of the resilient arm 5. In order that the locking member shall be capable of cooperating with the butt member 6 on the arm 5, the butt member 6 must extend a certain distance outside the resilient arm 5 at that side thereof at which the locking member issituated. However it is also possible to let the'locking member 11 extend through a slot extending along the central line of the resilient arm 5, the butt member then being arranged symmetrically with respect to the central line of the re silient arm.

The upper surface of the butt member 6 and the surface 13 on the locking member 11 need not necessarily have the V-shape shown on the figures, but they should however be so formed that the leaf spring 7 when actuating the butt member 6 or the locking member 11 during its downward movement is flexed to one or the other side as appears from Figure 2 or Figure 4 respectively. Espe cially it should be noted that the surface 13 on the locking member 11 should be so formed that the force exerted by the leaf spring 7 on the locking member will have the correct direction, i. e. so that the locking member is l atented Feb. 4, was

moved out of engagement with the butt member 6 and When the leaf spring -7 .is:restored,to itsinitialposition;

from the position shownin Figure 2, ,ittmayhappenthat during part of the movementathe lower-end of the leaf spring 7 will be pressed; against the extension 14 of the locking member ll-thereby exerting a turning moment on the locking member which moment-acts intadirection opposite to that of the moment caused by the spring 12. Therefore the spring 12- should be soarranged and dimensioned that-the'moment exerted by it on-thelocking member 11 is larger than the said moment caused by-the leaf spring 7 so that thelocking member 11 is not moved out ofthe locked position, whentthe-leafspring 7 is restored from the position shown inFigure 2.

The switch is of course providedflwith meansvforcconnecting itinto a circuit- Since tthese-meanslare not of interest in connection withthe invention they have-not been shown on the drawing.

The embodiment described above in 'conjunctionwith the drawing is given by way of'example only and can be varied andmcdified in many ways :within the scope of the invention. Thus the required directional force on the locking member'can be produced in other ways than by means ofthe spring 12, e. g: by giving the lever-such a shape that it strives to rotate in the desired direction under theinfluence .of gravity. However in the latter casetthe switch-will work satisfactorily only when mounted in certain positions. Furthermorethe locking member need not be pivoteduon a post as in the shown embodimentbut can also be attached to a spring which in turn is attached to theframe of the switch and exerts a pressure on the lockingmember in the desired direction,

The operating member 7 need not necessarily be oper ated by means of,- a push button but can be adapted to be operated by e. by-thearmatnre of a. relay or the like.

Whatis claimed is:

1.. An electricswitch comprising: a fixed contact; a re silient arm carrying a movable contact thereon adapted to engage the fixed contact in operated position; a butt mem her on said resilient arm;.adisplaceable operating means for acting upon said 'buttrnember to move the resilient arm and the movabletcontacttfromnon-operated to operated position; first spring-meansfor restoring said operating member to its home position after it has been operated; a locking member;.second spring means acting upon said locking memberfor moving it into engagement with said buttrnember when :the resilient arm isumoved into.

operated position, .saidlocking member havingua surface located in. thepath of travel of saidoperating means when thelocking member is in engagement with. said butt :memher, and said operating.'meansbeingtengageable with said surface to move saidlockingtmember out of engagement with said butt member.

2. An electric switch rcomprisingi a fixedlcontact.rnem 7 4 ated position; said butt member having a concave surface facing one end of said leaf spring when said resilient arm is in non-operated position so that the leaf spring when displaced a first time acts upon said butt member to move the resilient arm into operated position; and said locking member having a concavesurfacefacing said one end of the leaf spring when the locking member is in locking position so that the leaf spring'when displaced a second time acts upon saidlock'ing member to move item of locking'position, thereby'releasing the resilient arm.

3. An electrical switch comprising: a fixed-contact; a resilient arm carrying a movable contact thereon; a butt 1 member attached'to said resilient'arm; a'leaf'springwhich is longitudinallydisplaceable against the action of a restoring spring; a lever pivoted at one end and having a hook-shaped extension at the other endyspring means acting upon said lever, said hook-shaped extension of the 1 lever. having aniouter side abutting against said butt memberiwhenthe'resilient arm is innon-operated position and catching said buttmem'ber when-the resilient arm is in operated position to retain theresilient arm in' operated position; said butt member having a concave surface facging one end of said leaf spring so :thatthe leaf spring when displaced a first time acts upon said buttmember, thereby movingthe' resilient 'EI'IDI lHtUOPeI'EilCCd' position, and said lever having a concave surface'facing said one end of saidleaf spring when the lever is in'a position in which *rsaid hook-shapedextensioncatches the butt member, so

that the leafspringwhen operated 'a second time acts upon said'lev'er tomove' said hook-shaped extension away from 'said butt membeifi'thereby' releasing said resilient arm.

4. "Aswitch comprising? a 'fi'xedcontact', a resilient leaf spring contact'armmaving a movable contact thereon adapted to engage such'fixed contact in operated position, said'le'afspringbeingbiased away'from said fixed contact; a i reciprocable resilient operating means normally spring r ;urged away from said contact arm; butt means onsaid contact "arm haying a' surfacet for cooperating with said operatingmeans, said opearting means being enga-geable with saidsurface todisplace said arm and causethe movable contact to engagetheifixedcontact; lock'means nor- ;mally'urged'towardssaid butt'means and engagingthe samewhenthecontactarm is'moved into operated position to'retainsaid ar-rn and movable contact in operated position, said lock means having a surface for cooperating with s'aid'ope'rating 1 means; saidoperating means being engageablewith' said-surface to displace said lock means with sa'id' butt member to retain said resilient'arm in:o per- V ariddisengageit from said buttmeans so that the'contaet arm isdisplaced' from" operated position thereby breaking the contacts.

"Referencs 'cited -in-tlie=file of this patent "UNITED STATES PATENTS ..'3.04',557 .Pirnie -;Sept. 2, 1884 l,0Sl;2l9' Grabau :Jan. 21-, 1913 1,424,402 "Hartman Aug'l, 1922 FOREIGN PATENTS 1660,341 Germany .May 21, 1938 

